All issues
Volume 46, Issue 7
Displaying 1-8 of 8 articles from this issue
- |<
- <
- 1
- >
- >|
Paper
Measurement
-
Akimasa SUZUKI, Taketoshi IYOTA, Shinya USAMI, Kazuhiro WATANABE2010 Volume 46 Issue 7 Pages 357-364
Published: 2010
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSThis paper describes a real-time processing of indoor positioning system using SS (spread spectrum) ultra sonic waves. For code acquisition, it is required to obtain correlation values between the received ultra sonic signals and replica signals. Moreover a real-time processor for correlation values is indispensable part to build a positioning system for practical use. In our case, the real-time processing means that 16000 data of received signals must be processed in only 6 micro seconds (one sampling cycle time). Under such limited conditions, even if a dedicated hardware is constructed on a FPGA, a real time processing to obtain correlation values is hard to be realized without new algorithm ideas. Therefore, a real-time processing hardware utilizing the new algorithm named Stored Partial Correlation Method was developed in this paper. The paper also conducts experiments of range measurements to compare results by Stored Partial Correlation Method and ordinary off-line processing. As a result, outputs with real-time correlator have almost the same values as those with ordinary off-line processing. Furthermore, the real-time processing of correlation calculation is achieved within 5.76 micro seconds .View full abstractDownload PDF (850K)
Control
-
Hiroyuki KONDO, Yoshimasa OCHI2010 Volume 46 Issue 7 Pages 365-372
Published: 2010
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSThis paper describes a design method of an I-PD (proportional-derivative preceded integral) controller. This method, which consists of two stages, is simple compared with conventional ones. Specifically, first an original high-order plant is reduced to a second-order system in terms of the ν-gap metric as a criterion of the modeling error, and next the control gains are obtained as state feedback gains of the integral-type optimal servomechanism (IOS) for an augmented system. The resultant controller is exactly an I-PD one. Although perfect closed-loop stability and control performance are not guaranteed due to the modeling error, if the ν-gap is small enough, it is probable for these properties to be adequately preserved. Moreover, it can be transformed into a one-degree-of-freedom PID (proportional-derivative-integral) controller and a PI-D (derivative preceded proportional-integral) one in order to use a suitable type of the controllers depending on the plant or control objective. Design examples and simulation results are shown to demonstrate the effectiveness and usefulness of the proposed method.View full abstractDownload PDF (716K) -
—Attitude Control Experiment—Hiroyuki ICHIHARA, Masakatsu KAWATA2010 Volume 46 Issue 7 Pages 373-382
Published: 2010
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSThe dynamics of acrobots, two-link underactuated system, have strong nonlinearity, so that gain scheduling (GS) control is suitable for stabilizing the system in a wide range of operation. In this paper, GS controller design problems for the attitude control are reduced to solving polynomially parameter-dependent linear matrix inequalities (PDLMIs). The polynomially PDLMIs are relaxed by matrix sum of squares (SOS) polynomials to find feasible solutions. Several reduction techniques are adopted to reduce the amount of computation for solving the SOS problems while direct formulations are too computationally expensive to solve. For two attitude modes of the acrobot, the effectiveness of GS control is shown by experiments as well as nonlinear simulations.View full abstractDownload PDF (1345K) -
Kazuyuki KON, Hiroaki FUKUSHIMA, Fumitoshi MATSUNO2010 Volume 46 Issue 7 Pages 383-390
Published: 2010
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSIn this paper, multi-vehicle formation control with collision avoidance method based on model predictive control (MPC) is proposed. Since MPC based methods can only consider collision avoidance at discrete time steps, a collision may occur in intervals between prediction time steps. In order to prevent this problem, we propose a method which guarantees the collision avoidance not only at prediction time steps but also in intervals between them. The proposed method constrains transition of collision avoidance constraints to exclude possibilities of collisions between time steps. Numerical examples and experiments show the effectiveness of the proposed method.View full abstractDownload PDF (1293K)
Systems and Information
-
Yoshikatsu HAYASHI, Yurie TAMURA, Kazuya SASE, Ken SUGAWARA, Yasuji SA ...2010 Volume 46 Issue 7 Pages 391-400
Published: 2010
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSPrediction mechanism is necessary for human visual motion to compensate a delay of sensory-motor system. In a previous study, “proactive control” was discussed as one example of predictive function of human beings, in which motion of hands preceded the virtual moving target in visual tracking experiments. To study the roles of the positional-error correction mechanism and the prediction mechanism, we carried out an intermittently-visual tracking experiment where a circular orbit is segmented into the target-visible regions and the target-invisible regions. Main results found in this research were following. A rhythmic component appeared in the tracer velocity when the target velocity was relatively high. The period of the rhythm in the brain obtained from environmental stimuli is shortened more than 10%. The shortening of the period of rhythm in the brain accelerates the hand motion as soon as the visual information is cut-off, and causes the precedence of hand motion to the target motion. Although the precedence of the hand in the blind region is reset by the environmental information when the target enters the visible region, the hand motion precedes the target in average when the predictive mechanism dominates the error-corrective mechanism.View full abstractDownload PDF (1032K)
System Integration
-
Masahiro INOUE, Osamu FUKUDA, Masayoshi TSUBAI, Satoshi MURAKI, Hirosh ...2010 Volume 46 Issue 7 Pages 401-407
Published: 2010
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSBalance between human body composition, e.g. bones, muscles, and fat, is a major and basic indicator of personal health. Body composition analysis using ultrasound has been developed rapidly. However, interpretation of echo signal is conducted manually, and accuracy and confidence in interpretation requires experience. This paper proposes an automated discrimination method of tissue boundaries for measuring the thickness of subcutaneous fat and muscular layers. A portable one-dimensional ultrasound device was used in this study. The proposed method discriminated tissue boundaries based on tissue elasticity. Validity of the proposed method was evaluated in twenty-one subjects (twelve women, nine men; aged 20-70 yr) at three anatomical sites. Experimental results show that the proposed method can achieve considerably high discrimination performance.View full abstractDownload PDF (1188K) -
Osamu FUKUDA, Natsuko NABEOKA, Daisuke HASHIMOTO, Masaaki OKUSHI2010 Volume 46 Issue 7 Pages 408-414
Published: 2010
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSUp to the present time, estimation of Beef Marbling Standard (BMS) number based on ultrasound echo imaging of live beef cattle has been studied. However, it is difficult to establish the objective and high accurate estimation method. Therefore, this paper proposes a novel modeling technique based on a neural network to estimate the BMS number. The proposed method consists of three process steps: the extraction of texture features, principal component analysis, and the estimation of BMS number by the neural network. The neural network can be expected to model the non-linear mapping between the texture features and the BMS numbers. In the verification test with 27 live beef cows, the proposed method achieved high estimation performance. The correlation coefficient between estimated and actual BMS numbers was r=0.88 (P<0.01) by leave-one-out method. On the other hand, the correlation coefficient by conventional multple regression analysis was r=0.51(P<0.01). These results showed that the proposed method was effective in non-linear modeling between the texture features and the BMS numbers.View full abstractDownload PDF (1058K)
Short Paper
-
Tatsuya KAI, Katsunori KONDOU2010 Volume 46 Issue 7 Pages 415-417
Published: 2010
Released on J-STAGE: November 03, 2011
JOURNAL FREE ACCESSThis paper addresses control of a 3D space robot of two rigid bodies with initial angular momentum. First, we explain the universal joint model with initial angular momentum. We next apply model predictive control to an attitude control problem of the universal joint model with initial angular momentum, and show a simulation result to confirm reduction of calculation amount. Then, a simulation with a modeling error of initial angular momentum is performed in order to check robustness.View full abstractDownload PDF (340K)
- |<
- <
- 1
- >
- >|